1. This swimming pool energy cost study was originally conducted on March 1, 1988 and
its results are summarized by the first graph in Illustration 14. The study was updated on
November 22, 2000 and the new results are shown in Illustration 15.
2. Your costs may be higher or lower based on the cost of energy in your state and the type
of fuel or heating system you are using.
3. Fuel oil and propane systems range from 60-70% efficiency. Natural gas systems range
4. Heat pumps were wound to be 440% efficient on the average; based on the C.O.P.
specifications of 13 heat pumps. Newer systems are slightly higher in the range of 650%.
5. "Coefficient of Performance" is the ratio of BTU output to the BTUS used [input] of a
heater. PCS1 C.O.P. is 60000 ÷ 1351 = 44. Efficiency = C.O.P. x 100 = 4400%. This is the
standard method used to compare performance against electric resistance heaters. The term BTU
means British Thermal Unit and is the amount of energy required to raise one gallon of water one
degree Fahrenheit. The THERM is a standard unit of expression and is equal to 100,000 BTUS.
6. In order to get one therm of energy into the pool, the efficiency of the heating system
must be considered. It takes 142,857 BTUS input on fuel oil and propane to get 100,000 btus
output of the system [input for the pool] at 70% efficiency. It takes 125,000 BTUS input to get
100,000 output [input to the pool] in a natural gas system with 80% efficiency.
7. This study assumes a new pool heater is being purchased. It therefore uses the most
favorable efficiency ratings.
8. Installed systems with lower efficiencies will cost more to operate.
9. In 1988, the cost of energy had gone down making heat pump operating costs the same
or higher than 80% natural gas heaters. A heat pump may not yield a payback when compared to
an 80% efficient gas heater. The SolarAttic PCS1 does.
10. This study is based on the heat requirements of a 17 x 35 foot pool with 22-25000
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